In situations where power drill operators drill a great number of holes, such as in aircraft manufacture, the drills must be frequently changed because of dullness or because of requirement for a different size. Standard power drills have Jacobs-type chucks which require the operator to loosen and tighten the chuck every time a used drill is removed and a new drill is inserted. Needless to say, when multiple holes are being drilled by an operator, this type of drill changing which is frequent during a day, consumes an inordinate amount of time.
In the prior art, quick change drills have been manufactured by a brazing an adapter to each drill and then finishing the assembly by multiple grind operations to make the adapter concentric with the drill. This method has the disadvantage of being very expensive. It requires a high initial cost for the brazing apparatus and grinding equipment so as to limit producers of this type to drill manufacturers that have elaborate brazing and grinding facilities. When this equipment is available, the products are expensive.